Fan system and seriate starting module and delayed starting unit thereof

ABSTRACT

A fan system for receiving an input voltage from exterior includes a first fan module, a second fan module and a seriate starting module. The seriate starting module is electrically connected with the first fan module and the second fan module. The seriate starting module receives the input voltage and starts the first fan module according to the input voltage, and starts the second fan module according to the input voltage after the first fan module is started for a predetermined time.

CROSS REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 094140585 filed in Taiwan, Republic of China on Nov. 18, 2005, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a fan system and a seriate starting module and a delayed starting unit thereof, and, in particular, to a fan system having a plurality of fan modules, and a seriate starting module and a delayed starting unit of the fan system.

2. Related Art

Generally speaking, a large electronic system is always equipped with a fan system to ensure that the electronic system can be kept at the normal working temperature such that the electronic system can operate normally.

FIG. 1 is a schematic illustration showing a conventional fan system 1 disposed in an electronic system (not shown). The fan system 1 receives an input voltage V_(in) from exterior to serve as an operation voltage. The fan system 1 mainly has a starting module 11 and a plurality of fan modules 12 a to 12 n. After the starting module 11 receives the input voltage V_(in), the fan modules 12 a to 12 n are started simultaneously to dissipate the heat. However, when the fan modules 12 a to 12 n are started simultaneously, an extremely large start-up current and inrush current are generated at the moment of starting. Thus, the electronic system or the fan system 1 may crash or have unpredictable malfunction, or even the electronic system or the fan system 1 may be damaged.

As shown in FIG. 2, another conventional fan system 1′ has a plurality of starting modules 11 a to 11 n corresponding to the fan modules 12 a to 12 n so as to start the fan modules 12 a to 12 n, respectively.

In view of the above-mentioned problems, the prior art adopts an analog starting control chip for starting the fan modules 12 a to 12 n in sequential, or a software module to control the starting sequence of the fan modules 12 a to 12 n. Thus, the prior art provides a protection mechanism for respectively starting the fan modules 12 a to 12 n at different time instants so as to avoid the malfunction caused when the fan modules 12 a to 12 n are simultaneously started. However, the analog starting control chip has a high price, and the software module has a complicated architecture. Thus, the overall manufacturing cost of the conventional fan system 1 is too high. In addition, the analog starting control chip only can delay the starting time of each of the fan modules 12 a to 12 n and cannot provide the function of soft-start.

Thus, it is an important subject of the invention to provide a fan system and a seriate starting module and a delayed starting unit thereof to overcome the above-mentioned problems.

SUMMARY OF THE INVENTION

In view of the foregoing, the invention is to provide a fan system and a seriate starting module and a delayed starting unit thereof for starting a plurality of fan modules at different time instants in a seriate manner so as to avoid the malfunction caused when the fan modules are started simultaneously.

In addition, the invention is also to provide a fan system and a seriate starting module and a delayed starting unit thereof having the resetting effect to discharge the residual charges in the fan system and thus avoid the malfunction.

To achieve the above, a fan system of the invention is for receiving an input voltage from exterior. The fan system includes a first fan module, a second fan module and a seriate starting module. The seriate starting module, which is electrically connected with the first fan module and the second fan module, receives the input voltage, starts the first fan module according to the input voltage, and starts the second fan module according to the input voltage after the first fan module is started for a predetermined time.

Furthermore, the invention also discloses a method of resetting a delaying circuit, which is coupled with an input voltage from exterior and has a capacitor and a switch element. The switch element receives the input voltage and is electrically connected with the capacitor and grounded. The method includes the steps of: separating the delaying circuit from the input voltage, turning on the switch element, and forming a discharge path from the capacitor to the switch element so as to perform a discharging operation.

As mentioned above, the fan system and the seriate starting module and the delayed starting unit thereof according to the invention can sequentially start a plurality of fan modules at different time instants so as to avoid the malfunction caused by the extremely large start-up current and inrush current, which are generated by instantaneously starting the fan modules. The fan modules are started in a time-sharing manner to ensure that the fan system can operate normally, prevent the electronic system and the fan system from being damaged, and replace the analog starting control chip to reduce the overall manufacturing cost. In addition, the invention further possesses the reset function of discharging the charges remained in the fan system so as to prevent the malfunction from occurring.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein:

FIG. 1 is a schematic illustration showing a conventional fan system;

FIG. 2 is a schematic illustration showing another conventional fan system;

FIG. 3 is a schematic illustration showing a fan system according to a preferred embodiment of the invention; and

FIG. 4 is a circuit diagram showing a fan system according to the preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.

FIG. 3 is a schematic illustration showing a fan system 2 according to a preferred embodiment of the invention. As shown in FIG. 3, the fan system 2 may be applied to an electronic system (not shown) in order to dissipate heat. The fan system 2 receives an input voltage 91 from exterior to serve as an operation voltage. The input voltage 91 may be supplied from the electronic system. The fan system 2 includes a first fan module 21, a second fan module 22 and a seriate starting module 23. Each of the first fan module 21 and the second fan module 22 has a fan. Of course, the user may dispose a plurality of fans in each of the first fan module 21 and the second fan module 22 according to the heat dissipating requirement so as to enhance the heat dissipating effect.

The seriate starting module 23 includes a starting unit 231 and a delayed starting unit 232. The starting unit 231 electrically connected with the first fan module 21 receives the input voltage 91 and starts the first fan module 21 according to the input voltage 91. The delayed starting unit 232 includes a starting circuit 233 and a delaying circuit 234. The starting circuit 233, which is electrically connected between the second fan module 22 and the delaying circuit 234, receives the input voltage 91. The delaying circuit 234 controls the starting circuit 233 to start the second fan module 22 according to the input voltage 91 after the first fan module 21 is started for a predetermined time.

Then, the fan system 2 of this embodiment starts the second fan module 22 after the first fan module 21 is started for the predetermined time, such that the first fan module 21 and the second fan module 22 can be started at different time instants. Thus, it is possible to avoid the malfunction caused by the extremely large start-up current and inrush current, which are generated when the first fan module 21 and the second fan module 22 are started simultaneously.

In addition, FIG. 4 is a circuit diagram showing a fan system according to the preferred embodiment of the invention. Referring to FIG. 4, the delayed starting unit 232 includes a starting circuit 233 and a delaying circuit 234. The starting circuit 233 has a plurality of diodes D₁ to D₄, a plurality of resistors R₁ and R₂, a first switch element Q₁, a second switch element Q₂, a plurality of capacitors C₁ and C₅. The second switch element Q₂ electrically connected with the first switch element Q₁ through the diode D₃ controls the first switch element Q₁. In addition, the delaying circuit 234 is electrically connected with the first switch element Q₁ through the diodes D₁, D₂ and is further electrically connected with the second switch element Q₂ through the resistor R₉. To be noted, the dispositions of the diodes D₁, D₂ and the resistor R₉ are used to make the starting circuit 233 more stable, and are omissible.

Each of the first switch element Q₁ and the second switch element Q₂ may be a transistor or any other electronic element with the switch function. In this embodiment, the first switch element Q₁ is a PMOS transistor, and the second switch element Q₂ is an NMOS transistor. In addition, the diodes D₁ and D₂ are connected in parallel. Each of the diodes D₁ and D₂ has a first terminal for receiving the input voltage 91. In this embodiment, each of the diodes D₁ and D₂ may be a Schottky diode for avoiding the reverse current. One terminal of the resistor R₁ is electrically connected with a second terminal of each of the diodes D₁ and D₂.

A source S of the first switch element Q₁ is electrically connected with the second terminals of the diodes D₁ and D₂ to receive the input voltage 91. A drain D of the first switch element Q₁ is electrically connected with the second fan module 22 and is used to start the second fan module 22. A drain D of the second switch element Q₂ is electrically connected with the second terminals of the diodes D₁ and D₂ through the resistor R₁. The drain D of the second switch element Q₂ is further electrically connected with a gate G of the first switch element Q₁ through the diode D₃. A gate G of the second switch element Q₂ is electrically connected with the delaying circuit 234 through the resistor R₉.

A first terminal of the diode D₃ is electrically connected with the drain D of the second switch element Q₂. A second terminal of the diode D₃ is electrically connected with the gate G of the first switch element Q₁. A first terminal of the diode D₄ is electrically connected with the source S of the first switch element Q₁. A second terminal of the diode D₄ is electrically connected with the second terminal of the diode D₃. A first terminal of the capacitor C₁ is electrically connected with the source S of the first switch element Q₁, and a second terminal of the capacitor C₁ is electrically connected with a first terminal of the resistor R₂. A second terminal of the resistor R₂ is grounded.

The delaying circuit 234 includes a third switch element Q₃, a fourth switch element Q₄, a fifth switch element Q₅, a sixth switch element Q₆, a comparator U₁, a plurality of resistors R₃ to R₈ and R₁₂ to R₁₄, at least one capacitor C₂ and at least one diode D₅. Each of the third switch element Q₃, the fourth switch element Q₄, the fifth switch element Q₅ and the sixth switch element Q₆ may be a transistor or any other electronic element with the switch function. In this embodiment, each of the third switch element Q₃, the fifth switch element Q₅ and the sixth switch element Q₆ is an NPN transistor, and the fourth switch element Q₄ is a PNP transistor.

A base B of the third switch element Q₃ electrically connected with a first terminal of the resistor R₃ receives the input voltage 91. A collector C of the third switch element Q₃ is electrically connected with the diodes D₁ and D₂ through a resistor R₅. An emitter E of the third switch element Q₃ and a resistor R₄ are grounded.

A base B of the fourth switch element Q₄ is electrically connected with the collector C of the third switch element Q₃. An emitter E of the fourth switch element Q₄ is connected with an external power VCC.

The resistor R₆ has a first terminal, which is electrically connected with a collector C of the fourth switch element Q₄, and a second terminal.

The capacitor C₂ has a first terminal, which is electrically connected with the second terminal of the resistor R₆ through the diode D₅, and a second terminal grounded. In addition, the capacitor C₂ starts to charge and generate a control signal V₁ at the first terminal of the capacitor C₂ when the fourth switch element Q₄ turns on.

The comparator U₁ has a first input terminal input₁, a second input terminal input₂ and an output terminal output. In this embodiment, the first input terminal input₁ is a noninverting input terminal and the second input terminal input₂ is an inverting input terminal. The first input terminal input₁ is electrically connected with the second terminal of the resistor R₆. The second input terminal input₂ is electrically connected with the resistors R₇ and R₈, and the resistors R₇ and R₈ form a voltage-dividing circuit and provide a reference signal V_(ref) to the second input terminal input₂. The output terminal output, which is electrically connected with the gate of the second switch element Q₂ through the resistor R₉, controls the second switch element Q₂.

A collector C of the fifth switch element Q₅ is electrically connected with the first terminal of the capacitor C₂. An emitter E of the fifth switch element Q₅ is grounded. A collector C of the sixth switch element Q₆ is electrically connected with a base B of the fifth switch element Q₅. A base B of the sixth switch element Q₆ is electrically connected with the input voltage 91 through the resistor R₁₂, and an emitter E of the sixth switch element Q₆ is grounded.

A first terminal of the resistor R₁₂ receives the input voltage 91. A second terminal of the resistor R₁₂ is electrically connected with a first terminal of the resistor R₁₃. A second terminal of the resistor R₁₃ is grounded. Both of the resistors R₁₂ and R₁₃ form a voltage-dividing circuit. The base B of the sixth switch element Q₆, which is electrically connected with the second terminal of the resistor R₁₂, receives the divided input voltage. A first terminal of the resistor R₁₄ is electrically connected with the collector C of the sixth switch element Q₆. A second terminal of the resistor R₁₄ is electrically connected with the starting unit 231.

The starting unit 231 mainly includes a plurality of diodes D₆ to D₉, a plurality of resistors R₁₀ and R₁₁, two switch elements Q₇ and Q₈ and a plurality of capacitors C₃ and C₄. The diodes D₆ to D₉, the resistors R₁₀ and R₁₁, the switch elements Q₇ and Q₈ and the capacitor C₃ have the same constructions and functions as those of the diodes D₁ to D₄, the resistors R₁ and R₂, the switch elements Q₁ and Q₂ and the capacitor C₁, so the detailed descriptions thereof will be omitted. In addition, the capacitor C₄ is electrically connected with the base B of the fifth switch element Q₅ and the collector C of the sixth switch element Q₆ through the resistor R₁₄.

The operation principle of the fan system 2 will be described in the following. First, after the seriate starting module 23 receives the input voltage 91 at a first time, the starting unit 231 and the delayed starting unit 232 simultaneously receive the input voltage 91 as the operation voltage.

The diodes D₆ and D₇ of the starting unit 231 receive the input voltage 91 such that the switch element Q₈ turns on and the capacitor C₃ starts to charge until the voltage value of the capacitor C₃ reaches the turn-on voltage of the switch element Q₇. When the switch element Q₇ turns on, the first fan module 21 starts to work. In this embodiment, the charging circuit of the capacitor C₃ and the resistor R₁₁ enables the current flowing through the first fan module 21 to increase at a slow rate such that the effect of soft starting can be achieved.

The delaying circuit 234 receives the input voltage 91, the third switch element Q₃ and the fourth switch element Q₄ turn on, and the capacitor C₂ starts to charge to generate the control signal V₁. After the predetermined time, the voltage value of the control signal V₁ is larger than the voltage value of the reference signal V_(ref), and the output terminal output outputs a positive voltage value to the gate of the second switch element Q₂ to control the second switch element Q₂ of the starting circuit 233 to turn on. To be noted, the predetermined time is determined according to the charging time of the capacitor C₂ and the resistor R₆. The user can select the different capacitor C₂ and resistor R₆ according to the to-be-delayed time so as to adjust the predetermined time. Alternatively, when the resistor R₆ is a variable resistor, adjusting the resistance of the resistor R₆ can adjust the predetermined time.

After the second switch element Q₂ turns on, the capacitor C₁ starts to charge. When the voltage value of the capacitor C₁ reaches the turn-on voltage of the first switch element Q₁, the first switch element Q₁ turns on to start the second fan module 22 in a soft-starting manner.

In addition, the fan system 2 of this embodiment further has the reset function, and the reset method is described in the following. After the seriate starting module 23 receives the input voltage 91, the switch elements Q₇ and Q₈ turn on, the sixth switch element Q₆ of the delaying circuit 234 turns on according to the voltage-dividing operation of the resistors R₁₂ and R₁₃, and the capacitor C₄ starts to charge. At this time, the potential of the base B of the fifth switch element Q₅ is about zero, which means that the fifth switch element Q₅ is off. When the user removes the fan system 2 from the electronic system, that is, when the sending of the input voltage 91 is stopped, the capacitor C₄ starts to discharge, and the voltage drop generated by the resistor R₁₄ serves as a tum-on voltage to turn on the fifth switch element Q₅. At this time, the capacitor C₂ can form a discharge path through the fifth switch element Q₅ so as to discharge the charges stored in the capacitor C₂ and thus achieve the reset effect. Thus, the malfunction can be avoided when the user inserts the fan system 2 back to the electronic system at the next time. Consequently, the fan system 2 of this embodiment starts the first fan module 21 and the second fan module 22 at different time instants using the seriate starting module 23 so as to achieve the effect of seriate starting and resetting. In addition, although only two fan modules are illustrated in FIG. 4, the number of fan modules can be adjusted according to the user's requirement.

In summary, the fan system and the seriate starting module and the delayed starting unit thereof according to the invention can sequentially start a plurality of fan modules at different time instants so as to avoid the malfunction caused by the extremely large start-up current and inrush current, which are generated by instantaneously starting the fan modules. The fan modules are started in a time-sharing manner to ensure that the fan system can operate normally, prevent the electronic system and the fan system from being damaged, and replace the analog starting control chip to reduce the overall manufacturing cost. In addition, the invention further possesses the reset function of discharging the charges remained in the fan system so as to prevent the malfunction from occurring.

Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention. 

1. A fan system for receiving an input voltage from exterior, the fan system comprising: a first fan module; a second fan module; and a seriate starting module electrically connected with the first fan module and the second fan module for receiving the input voltage, starting the first fan module according to the input voltage, and starting the second fan module according to the input voltage after the first fan module is started for a predetermined time.
 2. The fan system according to claim 1, wherein the seriate starting module comprises: a starting unit electrically connected with the first fan module for receiving the input voltage and starting the first fan module according to the input voltage; and a delayed starting unit electrically connected with the second fan module for receiving the input voltage and starting the second fan module according to the input voltage after the first fan module is started for the predetermined time.
 3. The fan system according to claim 2, wherein the delayed starting unit comprises: a starting circuit having a first switch element and a second switch element, wherein the first switch element receives the input voltage, and the second switch element is electrically connected with the first switch element to control the first switch element to start the second fan module; and a delaying circuit electrically connected with the first switch element and the second switch element for receiving the input voltage, and controlling the first switch element and the second switch element to start the second fan module after the first fan module is started for the predetermined time.
 4. The fan system according to claim 3, wherein the starting circuit further has at least one diode, and the diode has a first terminal for receiving the input voltage and a second terminal electrically connected with the first switch element.
 5. The fan system according to claim 4, wherein: each of the first switch element and the second switch element is a transistor; the first switch element has a source electrically connected with the second terminal of the diode, and a drain electrically connected with the second fan module; and the second switch element has a gate electrically connected with the delaying circuit, and a drain electrically connected with the second terminal of the diode and a gate of the first switch element.
 6. The fan system according to claim 5, wherein the first switch element is a PMOS transistor and the second switch element is an NMOS transistor.
 7. The fan system according to claim 3, wherein the delaying circuit comprises: a third switch element having one terminal for receiving the input voltage; a fourth switch element electrically connected with the third switch element; a first resistor having a second terminal and a first terminal electrically connected with the fourth switch element; a capacitor having a first terminal and a second terminal, wherein the first terminal of the capacitor is electrically connected with the second terminal of the first resistor, the second terminal of the capacitor is grounded, and the first terminal of the capacitor generates a control signal when the fourth switch element turns on; and a comparator having a first input terminal for receiving the control signal, a second input terminal for receiving a reference signal, and an output terminal electrically connected with the second switch element for controlling the second switch element.
 8. The fan system according to claim 7, wherein the delaying circuit further comprises a fifth switch element electrically connected with the first terminal of the capacitor, and a sixth switch element electrically connected with the fifth switch element.
 9. The fan system according to claim 8, wherein the delaying circuit further comprises: a second resistor having a second terminal and a first terminal receiving the input voltage; a third resistor having a first terminal electrically connected with the second terminal of the second resistor, and a second terminal grounded; and a fourth resistor having a first terminal electrically connected with the sixth switch element, and a second terminal electrically connected with the starting unit.
 10. The fan system according to claim 8, wherein the third switch element, the fourth switch element, the fifth switch element, and the sixth switch element are all transistors.
 11. The fan system according to claim 8, wherein the fifth switch element and the sixth switch element are electrically connected with the starting unit.
 12. The fan system according to claim 11, wherein the starting unit comprises another capacitor electrically connected with the fifth switch element.
 13. The fan system according to claim 7, wherein the predetermined time is determined according to a charging time of the first resistor and the capacitor.
 14. The fan system according to claim 7, wherein the first input terminal is a noninverting input terminal, and the second input terminal is an inverting input terminal.
 15. The fan system according to claim 7, wherein the first resistor is a variable resistor.
 16. The fan system according to claim 1, wherein each of the first fan module and the second fan module comprises at least one fan.
 17. A method of resetting a delaying circuit, wherein the delaying circuit is coupled with an input voltage from exterior and has a capacitor and a switch element, and the switch element receives the input voltage and is electrically connected with the capacitor and grounded, the method comprising the steps of: separating the delaying circuit from the input voltage; turning on the switch element; and forming a discharge path from the capacitor to the switch element so as to perform a discharging operation.
 18. The method according to claim 17, wherein the switch element turns on by a turn-on voltage provided by an additional capacitor.
 19. The method according to claim 18, wherein the switch element is a transistor.
 20. The method according to claim 17, wherein the switch element has a base for receiving the input voltage and electrically connected with the additional capacitor, a collector electrically connected with the capacitor, and an emitter grounded. 